Actuators are important components of the circuit breaker and the high-speed reversing switch. At present, there are spring actuators, electromagnetic actuators, and permanent magnetic actuators, etc. The spring actuators have the advantage that there is no need for a high-power direct-current power supply and have the defects of relatively complicated structure, more parts, and poor reliability. The electromagnetic actuators have a cumbersome structure and a relatively long switching-off and switching-on time.
The permanent magnetic actuators use a permanent magnet as a component for keeping the switching-off and switching-on positions. When the permanent magnetic actuators work, only one main moving component is provided, the switching-off and switching-on current is small, the mechanical service life is long, but the movement inertia of the moving component when in a switching-off state is relatively large, and a higher action speed cannot be achieved.
A typical actuator of a vacuum circuit breaker is disclosed in China patent CN 101315836 A (published on Feb. 13, 2008), the actuator mainly comprising an eddy-current disc, a switching-off coil, a switching-on coil and a charging circuit. When the charging circuit is excited, the rapidly-increased current would flow through the switching-off coil or the switching-on coil, and the switching-off coil or the switching-on coil will induce an eddy current in the eddy-current disc. In this way, a relatively large electromagnetic repulsive force can drive the eddy-current disc to leave the corresponding coil. The actuator further comprises a spring mechanism for keeping the switching-off state and the switching-on state. Although the switching-off operation can be rapidly realized by virtue of the electromagnetic repulsive force, the actuator has a large energy consumption and poor controllability.